gpsbabel suddenly based on qt5-mac thus leaving qt4-mac-based port qlandkartegt in limbo

[René J. V. Bertin]

Marko Käning wrote:

> How to transition from Qt4 to Qt5 more smoothly?? This is going to happen for
> many ports in the future, so, perhaps this is a port where one could try to
> exercise how to do it least disturbingly for users having installed qt4-mac
> ports?!
> 
> I - for my part - am still having a fully qt4-mac-based MacPorts system for
> production, which is why I don’t want such automagic transitions to Qt5,
> unless all dependent ports have also migrated to Qt5.
> 
> Any ideas?

Yeah, good luck with that.
What you want is a system that detects what the user has installed and adapts 
dependencies. The times I tried that my efforts were rejected because behaviour 
has to be deterministic. I implemented a port select feature for my own Qt4 and 
Qt5 ports, but apparently that's verboten too for ports that are dependencies 
for other ports (maybe because it's "implicit/hidden indeterminism").
You'd have to figure in the fact that not all projects will continue to provide 
the option to build against either Qt4 or Qt5 for as long as you'll want, partly 
because the transition to Qt5 has been going on quite a bit longer than what one 
might deduce from its presence in MacPorts.

Your best long-term option will be to configure your own port repository in which 
you keep the last "desirable" version of ports that no longer correspond to your 
requirements (a priori you should be able to do that with minimal modification if 
at all).

R.